OEM Lennox Pressure Switch — 33W14

The genuine OEM Lennox 33W14 pressure switch is a safety control that confirms proper draft and venting before your Lennox furnace ignites. It senses the negative pressure created by the inducer (draft) motor, verifying that combustion gases are being safely exhausted. Only when adequate pressure is detected does the switch close and allow the ignition sequence to proceed, preventing the furnace from firing under unsafe venting conditions.

Common failure symptoms: A failing pressure switch — or one responding to a blocked vent, cracked hose, or condensate buildup — will prevent the furnace from lighting, leaving you with no heat. Symptoms include the inducer motor running while the burners never ignite, repeated ignition lockouts, or an open-pressure-switch fault code on the control board. A stuck or contaminated switch may also cause intermittent, hard-to-diagnose no-heat calls.

Why OEM matters: The 33W14 is set to the precise actuation point (measured in inches of water column) required by your specific Lennox furnace. Using a switch with the wrong pressure rating can allow unsafe operation or cause constant nuisance lockouts. The OEM part guarantees the correct set point, port configuration, and hose fit, restoring safe and reliable furnace startup for your Lennox equipment.